Internal combustion engines, in particular diesel and gasoline engines, are frequently equipped with turbochargers. Generally, turbochargers are driven by and placed in the exhaust flow of an internal combustion engine. The exhaust flow and/or the intake airflow are controlled by one or more bypass valves located in branches of the exhaust and/or intake system, and ensure that various constraints are respected, including exhaust composition, compressor outlet temperature and turbine inlet temperature, as well as avoiding turbocharger surge or overspeed. Bypass valves that are actively controlled usually have a default or “failsafe” position into which they move when there is no vacuum or electrical supply. The failsafe position normally is either fully open or fully closed. The default setting is determined by factors such as safety and engine power requirements at altitude. However, the compressor bypass valve may also fail and become stuck, for example, in the fully closed or fully open position. It would be desirable to detect such failure of the compressor bypass valve without a position feedback sensor and its associated increased cost and complexity.